title: Carbohydrate binding and unfolding of Spatholobus parviflorus lectin: fluorescence and circular dichroism spectroscopic study.
abstract: Biophysical and carbohydrate binding studies have been carried out on a lectin of Spatholobus parviflorus (SPL) seeds isolated by affinity chromatography on cross-linked guar gum. It agglutinated erythrocytes of all ABO blood groups. SDS-PAGE, both in reducing and non-reducing conditions, showed two bands with MW of 29 and 31 kDa. MALDI TOF analysis revealed two peaks at 60 and 120 kDa, indicating that SPL is a hetero-dimeric tetramer. Temperature and pH stability studies revealed that SPL is a thermostable protein and its lectin activity is unaffected in the temperature range of 0-70 °C. Its activity was maximal in the pH range of 7-8. Unfolding studies with different denaturants like urea and guanidine hydrochloride indicated its globular nature and the presence of tryptophan in the highly hydrophobic area, which could be correlated to the results of fluorescence spectroscopic studies. The effect of carbohydrate binding on the lectin, shown by circular dichroism spectra, indicated the changes in its secondary and tertiary structures. SPL exerted anti-fungal activity against Aspergillus sp.
authors.affiliation: Molecular Biophysics Unit, Indian Institute of Science, Bangalore, 560012, India.
authors.forename: Geethanandan
authors.initials: G
authors.lastname: K
authors.forename: Abhilash
authors.initials: A
authors.lastname: Joseph
authors.forename: Sadasivan
authors.initials: S
authors.lastname: C
authors.forename: M
authors.initials: M
authors.lastname: Haridas
mesh_terms: D001234:Aspergillus niger / Q000187:drug effects; D050260:Carbohydrate Metabolism; D002942:Circular Dichroism; D007887:Fabaceae / Q000737:chemistry*; D005670:Fusarium / Q000187:drug effects; D019791:Guanidine / Q000494:pharmacology; D006384:Hemagglutination / Q000187:drug effects; D006863:Hydrogen-Ion Concentration; D008024:Ligands; D037121:Plant Lectins / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism* / Q000494:pharmacology; D011489:Protein Denaturation / Q000187:drug effects; D017421:Sequence Analysis; D013050:Spectrometry, Fluorescence; D013696:Temperature; D014508:Urea / Q000494:pharmacology
chemical_list: D008024:Ligands; D037121:Plant Lectins; D014508:Urea; D019791:Guanidine